Tubular heat exchanger



(I. A. BROWN. TUBULAR HEAT EXCHANGER. APPLICATION F'ILED MAY 2. 192i.

Patented Mar. 28, 1.922.

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TUBULAR MAT EXCHANGER.

Specification of Letters Patent.

Patented Mar. 28, 1922.

- Application filed May 2, 1921. Serial No. 466,121.

To all whom it may concern:

Be it known that I, CHARLES ANDERTON BROWN, a subject of the King ofGreat Britain, residing at 19 Hampstead Hill Gardens, London, N. VV.,England, have invented certain new and 'useful Improvements in orConnected with Tubular Heat Exchangers, (for which I have filed anapplication No. 8,715 in England, dated March 19, 1920,) of which thefollowing is a specification.

This invention relates to tubular heat exchangers suitable for coolingwater, oil, gas, air, steam or other fluids, or for heating orevaporating such fluids, of the kind composed of tubes or funnels havingtheir ends or one end bulged or expanded in flat sided hexagonal formand fitted and connected together and wherein the interstices betweenthe tube bodies are filled with the fluid to be treated and the activemedium is passed through the tubes or vice versa. In such tubularexchangers the tubes are disposed in staggered formation and the fluidstream passes through the interstitial space between any pair ofadjacent tubes and strikes against the outer surface of another tube soas to divide the stream and each half stream unites with another halfstream from another interstitial space, and so on in progress throughthe tube block.

The hexagonal end formation is advantageous excepting that with theknown regular form the interstitial spacing between the tube bodies hasbeen made the same in the directions normal to the flow of the dividedstreams and normal to the flow of the full or united half streams, sothat the pitch is unnecessarily great in the directions normal to theflow of the divided stream. This results in undue fluid friction in theinterstitial spaces owing to frequent changes in the velocity of flow,and in undue volume and weight of the fluid necessary to fill theinterstitial spaces. I

According to the present invention, the

advantage of the hexagonal end form is' retained but the arrangement issuch that interstitial spacing between the tube bodies in the directionsnormal to the flow of the divided streams is substantially less than inthe direction normal to the flow of the full or united half streams.Preferably the interstitial spacing between the tube bodies in thedirection normal to the flow of the divided streams is approximately onehalf of that in the direction normal to the flow of the full or unitedhalf streams.

With this construction for a given amount of heat transferred from thefluid passing through the tubes to the fluid passing through theinterstitial spaces or vice versa the frontal area or the area of thetube block measured over the surface containing the end faces of thetubes is reduced; the we1ght of fluid contained in the interstitialspaces is reduced; and the fluid friction and shock loss of the fluidpassing through the interstitial s aces is reduced.

These resu ts may be obtained in accordance with the invention either bymodification of the hexagonal bulged or expanded ends or by a specialconstruction of the tube bodies.

In order that the invention may be clearly understood and readilycarried into effect, I will now proceed to describe the same more fullywith reference to the accompanymg drawing in which Figure 1 is adiagrammatic end View of one embodiment of my invention and Figure 2 isa diagrammatic end view of a modified form.

Figure 3 is a sectional view of one of the tubes shown in Figure 1.

Figures 4, 5. 6, 1 views of modified forms of tubes.

Figures 10 and 11 are partly diagrammatic the full streams are shorterthan the other four sides which are equal. In-this and the other figuresof the drawing the direction of flow in the interstitial spaces isindicated by an arrow. I

In a modification the angles on the opposed corners whose diagonal liesin the direction of flow of the full streams are different from theother four angles which are equal.

In a further modification shown in Figure 2 only the opposite angles areequal and only the opposite parallel sides are equal.

In the constructions shown in Figures 1 and 2 the body of the tubeinstead of being circular as shown may be made with a crow 8 and 9 arefragmentary section of regular hexagonal form or of one ofthe modifiedhexagonal forms described above.

In a further'modification particularly applicable to heat exchangers ofthe type referred to and especially to those described in thespecification of my British Patent N 0. 140954 dated 9th July, 1919, theportions of the tube between thebody and the hexagonal end may be madeof one or other of" the modified hexagonal forms described above, or thebody'of the tube may be modified in a variety of ways, some of which,are given by way of example in Figures 4*9, the bulged or expanded ends2 being of one of the special hexagonal forms described above.

Referring particularly to the said Figures 49, Figure 4 shows a bodyportion 1 which is of circular cross section for the middle portion ofits length, a bulged or expanded end 2 of one of special hexagonal formsdescribed above, a connecting portion 4 which is gradually tapered andhas faces which are inclined to the axis of the tube and a connectingportion 5' averaging to both the hexagonal and circular forms. It willbe seen that this connecting portion 5 comprises flat faces 6 and curvedor conical faces 7 which alternate with one another around the tube. I

Figure 5 shows a-somewhat similar construction to Figure 4 in whichhowever the connecting and the point 8 is of hexagonal form.

Figure 6 shows another slightly modified form of the tube illustrated inFigure 4 in which the portions 7 are flat and inclined to the axis ofthe tube.

In Figures 7 and 8 the body 1 of the tube is of duodecagonal form inFigure 7 a portion 8 of hexagonal form leading to the tapered portion 4,and in Figure-8 portions 6 and 7 similar to those described above with.reference to Figures 4 and 5 leading to the portions 4.

In Figure 9 the body 1 which is circular for part of its length has aportion 10 of duodecagonal form with portions7 averaging to both formsand a portion 8 leading from 10 to the tapered portion 4;

any combinations of the forms illustrated in Figures 4 to'9 may be madeif desired and are contemplated by my invention and in any of theseforms the surfaces other than the hexagonal ends may be made helical ifdesired.

Figures 10 and 11 illustrate embodiments of the tubes are hexagonal, inFigure 1 the bodies 1 being regular hexagons and the ends 2 irregularhexagons as described above with reference to Figure 1, and the pitch ;0being less than the pitch P, while in Figure 11 the ends 2 are regularhexagons and the bodies portion 5 between the portion 4 the invention inwhich the bodies 1 of r 1 irregular hexagons, inthis case the pitch 7)being equal to the pitch P. it will be in width spaces N.

It will be understood that the various embodiment-s of the inventiondescribed above are given by way of example only and that manymodifications thereof coming within the spirit of the invention may bemade. lVhile as pointed out above the invention may be carried outequally by the modification of the hexagonal ends of the tubes or bymodification of the tube bodies the former manner of carrying theinvention into effect may be considered preferable as thereby thepossibility .of the tubes being incorrectly assembled is minimized.

What I claim and desire to secure by Letters Patent of the United Statesis 2- 1. A tubular heat exchanger composed of tubes having polygonalexpanded or bulged ends, the width of the shoulder formed at thejunction of each tube bod with the. ex panded end being substantia 1yless in the directions normal to the flow of the divided streams offluid than the width in the directions normal to the flow of the full orunited half streams, substantially as and for the purpose specified. v

2. A tubular heat exchanger composed of tubes having expanded or bulgedends fitted and connected together, the difieren'ce in the radialdistance from the exterior surface to the center oft-he expanded end ofeach tube and the radial distance between the exterior surface andthecentler of the tube body being substantially less in the directionsnormal to the flow of the divided streams of fluid than the differencein the radial distances between corresponding points in the directionsnormal to, the fiow of the full or united half streams, substan tiallyas and for the purpose specified.

3. A tubular heat exchanger composed of tubes having expanded or bulgedends fitted and connected together, the ratio of the difference in theradial distance from the exterior surface to the center of the expandedend of each tube and the radial distance be tween the exterior surfaceand the center of the tube body in the directions normal to the flow ofthe divided streams of fluid to the difference in the radial distancebetween corresponding points in the directions normal to the flow of thefull or united half streams being approximately 1:2, substantially asand for the purpose specified.

4. A tubular heat exchanger composed of tubes having polygonal expandedor bulged ends fitted and connected together, the difference in thediameters of each tube body and its expanded end being substantiallyless in the directions normal to the flow of the divided streams offluid In both forms than the d'ifierence Lemma in the diameters in thedirections normal to the flow of the full or united half streams.

5. A tubular heat exchanger composed of tubes or funnels having theirends expanded or bulged in flat sided form and fitted and connectedtogether without end plates to form a tubeblock, the expanded ends beingof such modified hexagonal form that the interstitial spacing betweenthe tube 'bodies in the direction normal to the flow of the dividedstreams of fluid is substantially less than in'the directions normal tothe flow of the full or united half streams, substantially as and forthe purpose specified.

6. A tubular heat exchanger composed of tubes having their ends expandedor bulged in flat sided hexagonal form, fitted and connected together,the angles of said expanded ends of the tubes being equal, but the pairof opposite sides which are arranged par-- allel to the direction offlow of the full streams being shorter thanthe other four. sides whichare equal.

7. A tubular heat exchanger in accordance with claim 6 characterized bythe fact that the angles in the exposed corners whose 9. A tubular heatexchanger composed of tubes having irregular polygonal expanded ends,fitted and connected together, and the body portion of said tubes beingof regular polygonal form.

10. A tubular heat exchanger composed of tubes, having irregularpolygonal expanded ends fitted and connected together, the body portionof said tube being of regular poly onal form so that their diameters indirec tions normal to the flow of the divided streams are less than thediameters in the directions normal to the flow of the full or unitedhalf streams.

CHARLES ANDEBTON BROWN.

